1. Field of the Invention
The present invention relates to magneto-resistive heads, magnetic tapes and magnetic tape recording/reproducing systems.
2. Description of the Related Art
In recent years, video tape recorders, audio tape recorders and data storage systems for computers have been known as magnetic recording/reproducing apparatuses that use magnetic tapes as recording media. It is desirable for these magnetic recording media to have their recording density increased so as to improve their storage capacity and data transfer rate. However, when the recording density of a magnetic recording medium is increased, magnetic signals from the magnetic recording medium become weaker, and it is difficult to detect reproduction signals sufficiently with conventional inductive magnetic heads that utilize electromagnetic induction.
As such, it is becoming popular to use magneto-resistive heads, which use a magneto-resistive element (hereinafter referred to as MR element) comprised of a soft magnetic film, and which have a higher reproductive sensitivity than inductive magnetic heads, for the reproduction of signals. Further, of the various types of magneto-resistive heads, so-called shielded magneto-resistive heads, in which an MR element is placed between magnetic shields comprised of a soft magnetic material and in which an end portion of the MR element is exposed through a surface that faces a magnetic recording medium, have the highest reproductive efficiency, and are suitable for increasing recording density.
FIG. 10 shows the structure of a rotary head magnetic recording/reproducing apparatus that uses a conventional magneto-resistive head, and is a partially enlarged perspective view showing the rotary head and its surroundings. In order to place a magnetic tape 2 in contact with a magnetic head 1, the magnetic tape 2 is made to slide along a rotary drum 3, a lead 4, and rotary guides 5. The magnetic tape 2 is designed in such a manner that the lower edge of the tape runs along the lead 4 of the rotary drum 3 so that the magnetic head 1 can trace tracks correctly. By having the magnetic head 1, which is a magneto-resistive head that uses an MR element, mounted on the rotary drum 3 and made to slide along the magnetic surface of the magnetic tape 2, magnetic data recorded on the magnetic tape 2 is read.
FIGS. 11A and 11B show the sliding surface of a conventional magneto-resistive head. FIG. 11A is a front view of the magnetic head 1, and FIG. 11B is an enlarged front view of the MR element of the magnetic head 1 and its surroundings. The magnetic head 1 is positioned at a head exposing section formed at a predetermined position in the rotary drum 3, and an MR element 8 is held in place with a guard member 10 and a protective layer 9. The magnetic head 1 has such a structure where the MR element 8 is held between shields 6 and 7 comprised of a soft magnetic material, and where the surroundings of the shields 6 and 7 and of the MR element 8 are covered with the protective layer 9.
One end surface of the MR element 8 is exposed through the surface of the rotary drum 3 that contacts the magnetic tape 2, and the magnetic tape 2, which runs by sliding along the lead 4 of the rotary drum 3, and the MR element 8 face each other across a very small gap.